Ooh...it was quite a bit on the PTR but you SHOULD have been downloading most of it in the background already. I don't think anyone will be able to tell you the full size for sure

PTR sizes will always be big (especially if you don't have the client before). If you don't have the client before then it's hefty because it needs everything. Also during the PTR things will download and get overwritten again so it seems bigger than it should.